Serum Interleukin-38 and Tumor-Infiltrating Lymphocytes in Primary Brain Tumors.

Background: Tumor-infiltrating lymphocytes (TILs) and brain stromal cells produce immunosuppressive cytokines, contributing to an immunosuppressive tumor microenvironment (TME). Interleukin-38 (IL-38) is a novel anti-inflammatory cytokine and a natural modulator of the innate and adaptive immune system. However, its biological roles in brain tumors are not well defined. Objective: To assess the serum levels of IL-38 and the percentages of TILs in the tumor tissues of patients with primary brain tumors and to determine their associations with the pathological features of the disease. Methods: IL-38 was evaluated in sera using the enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (H&E)-stained sections were scored to determine the percentages of TILs in four different areas: the invasive margin, central tumor, perivascular and perinecrotic areas. Results: IL-38 serum levels were significantly higher in low- and high-grade tumors than in healthy individuals, meanwhile, its levels remained consistent between these two grades. Although no significant difference was found in IL-38 serum levels between different histological subtypes of brain tumors, its levels were significantly higher in intra-axial brain tumors than in extra-axial ones. Additionally, a significant positive correlation was observed between serum levels of IL-38 and tumor size in patients with low-grade tumors. TILs were detected in at least one of the four examined areas; however, no statistically significant correlation was found between IL-38 levels and TILs. Conclusion: Our data may suggest a connection between IL-38 and immune suppression and tumor progression in primary brain tumors. Further investigation is needed to uncover the role of IL-38 in the brain tumor microenvironment.

Frequent expression of CD45RO memory T cell marker as well as low to high expression of PD-1 and PD-L1 inhibitory molecules in seminoma and dysgerminoma.

BACKGROUND: Seminoma and dysgerminoma are rare testicular and ovarian germ cell tumors characterized by a significant infiltration of immune cells in the tumor microenvironment. According to the failure of conventional treatments in some patients, it is crucial to identify novel prognostic and therapeutic biomarkers for these patients. The objectives of this study were to evaluate the expression of CD45RO and PD-1/PD-L1 and investigate their association with the clinicopathological characteristics of the patients. METHODS: Immunohistochemistry was performed to assess the expression of CD45RO, PD-1, and PD-L1 in tumor-infiltrated lymphocytes (TILs), and tumor cells in 33 seminoma and 31 dysgerminoma patients. The expression levels were evaluated using a semiquantitative approach, weighted histoscore, which considers both the intensity and extent of staining. RESULTS: All seminoma and dysgerminoma patients exhibited CD45RO expression in TILs, with 66.7 % and 90.3 % displaying high levels of expression, respectively. PD-1 expression in TILs was observed at low levels in 81.8 % and 77.4 % and at high levels in 18.2 % and 19.4 % of seminoma and dysgerminoma patients, respectively. Likewise, low expression of PD-L1 in tumor cells was detected in 63.6 % of seminoma and 61.3 % of dysgerminoma patients, while none of the patients exhibited high expression of PD-L1. In seminoma patients, a positive correlation was observed between PD-1 expression in TILs and CD45RO expression and between PD-L1 expression in tumor cells and TILs score. CONCLUSION: The frequent infiltration of CD45RO, along with variable expression of PD-1 and PD-L1 on TILs and tumor cells, could impact the effectiveness of anti-tumor responses and immunotherapy.

Simultaneous Increase in Serum Levels of IL-37 and IL-18 Binding Protein In Low-Grade and High-Grade Brain Tumors.

BACKGROUND: IL-18binding protein (IL-18BP) might play a role in tumor escape from immune surveillance through interacting with IL-37. Such interactions modulate the antitumor activity of IL-18 and affect regulatory T cell (Treg) function. However, the biological roles of IL-37 and IL-18BP have not yet been explored in brain tumors. This study aimed to investigate serum levels of IL-37 and IL-18BP in high-grade and low-grade brain tumors and determine their associations with pathological characteristics of the patients. SUBJECTS AND METHODS: This case-control study consisted of 60 patients with brain tumors (40 low-grade and 20 high-grade) and 30 healthy controls. Enzyme-linked immunosorbent assay (ELISA) kits were used to measure the levels of IL-37 and IL-18BP in serum. RESULTS: Our results indicated that serum levels of IL-37 and IL-18BP were significantly higher in patients with brain tumors (109.02, 426.37 pg/mL), high-grade (104.44, 428.87 pg/mL), and low-grade (113.88, 426.37 pg/mL) tumors in compared to healthy controls (35.03, 362.00 pg/mL), (P<0.05). Interestingly, our results revealed a significant positive correlation between IL-37 and IL-18BP serum levels in brain tumors (n=60, R=0.42, P=0.001). Our study also showed that serum levels of IL-37 and IL-18BP in glioblastoma grade IV were approximately similar to those in astrocytoma grade II, meningioma type I, and pituitary adenoma. Furthermore, no significant differences were found in serum levels of IL-37 and IL-18BP between patients with low-grade and high-grade tumors (P=0.24 and P=0.61, respectively). CONCLUSION: The simultaneous increase in IL-37 and IL-18BP serum levels and their positive correlation may facilitate disease progression in low-grade and high-grade brain tumors by inhibiting antitumor immune responses.